My wife and I adopted an 83lbs Mastiff/Lab. A mix that is supposed to be generally tolerant of cats. This is proving not to be the case. I have read dozens of dog to cat introduction how-to guides. The main issue is that when the dog sees the cat, he immediately lunges. I hold him back (not easy) and my wife tries to redirect with treats and affection, but he is tunnel vision on the cat. There is no treat that interests him when this happens. Not even hotdog. He could care less and continues to lunge at the cat (behind a gate). So if I can't redirect with treats how in the world can we make progress? He also appears to get agitated at dogs that walk by the house. Again, there isn't a treat we've found that can redirect him. Please help, I will be devastated if we need to return him, but at this time I fear for the long term safety of my cat if we can't make progress. Thanks!!!